This invention relates to a printing apparatus and facsimile apparatus using the printing apparatus and, more particularly to a printing apparatus that performs printing in accordance with an ink-jet printing method and facsimile apparatus using the printing apparatus.
Conventionally, printers that perform printing in accordance with an ink-jet printing method employ various techniques as described below to detect the amount of residual ink in their ink tank.
Japanese Patent Application Laid-Open No. 2-102061 discloses a reflective type photosensor, with a reflection board provided in an ink tank, to detect shortage of ink. In Japanese Patent Application Laid-Open No. 56-144184, to avoid degradation of detection precision due to ripples of the ink surface, ink shortage status is detected after a predetermined period from stop of a carridge movement.
Further, for the residual ink detection, a current/voltage converter for converting a detected current into a voltage, and an A/D converter for converting the obtained analog voltage into a digital value are employed as well as a photosensor.
However, for the residual ink detection, to detect a photosensor output, the above prior art uses a circuit which requires adjustment due to fluctuation of the sensor output, the secular change of sensor characteristic, and variation in sensing mechanism, which exceed allowable values. Further, as the ink cartridge itself trembles due to vibration of the apparatus or the like, noise may be mixed in the residual-ink detection. Otherwise, in apparatuses where the ink cartridge integrated with the printhead into the carriage moves at each printing operation, the sensor output varies due to ripples of the ink surface, thus degrading the precision of residual-ink detection.